1. Field of the Invention
The present invention relates to a method for manufacturing a conductive organic molecular device using organic molecules with a conductivity property and, more particularly, to a method for manufacturing a nano-scale organic molecular device capable of improving reproducibility of a manufacturing process.
2. Description of the Related Art
Generally, a conductive organic molecular device that uses organic molecules with a conductive property (or a conductive organic semiconductor) is manufactured in various methods. As an instance, there is a method using self-assembly monolayer as an active layer [see Molecular Nanoelectronics, Chapter M, edited by American Scientific Publishers]. In this method, an insulating film SiN is formed on an upper and lower surface of a silicon (Si) substrate and then a hole with several micrometers diameter is formed in a lower portion of the substrate and the lower insulating film SiN. Also, a nano-sized pore is formed in the upper insulating film SiN at the top of the hole with an electron beam etching technique. The nano-sized pore takes a bowl shape with the opening at the upper edge. Next, a lower electrode is formed by evaporating a metal from the bottom side to fill the nano-sized pore and the substrate is immersed into a solution in which conductive organic molecules are dissolved. At this time, the conductive organic molecules are self assemble onto an exposed surface of lower electrode in the pore and form a highly ordered monolayer. After the conductive organic thin film is formed on the lower electrode, an upper electrode is formed on the conductive organic thin film. At this time, the upper electrode is formed by a method using a shadow mask or an ion milling method of depositing a conductive material on an entire substrate and then leaving only a portion of the conductive material [see Nano-scale molecular-switch devices manufactured by imprint lithography, Applied Physics Letters, Vol. 82-10, 2003 1610].
In the related art as described above, it is required to use dry etching equipment such as chemical reactive ion etching (RIE or ICP/RIE) equipment in order to form the nano-sized pore. Further, in order to form a clear pore, the upper insulating film has to be ion-etched for enough time. At this time, a residue such as a polymer may remain in the pore, which disturbs adsorption of a good quality of conductive organic molecules onto the lower electrode. In particular, because most of the conductive organic molecules adsorbed onto the lower electrode are damaged by acetone, solvent or the like, a photo-etching process cannot be implemented using a photoresist that includes the acetone or the solvent, and the like, after the conductive organic molecules are adsorbed onto the lower electrode.